Protective electrical device

ABSTRACT

The present invention is directed to a protective device that includes a cover assembly having a plurality of receptacle openings, a reset button and a test button. The reset button and the test button are disposed along a first diagonal and in opposite corners of a substantially square area defined by the reset button and test button. At least one receptacle contact structure includes a portion extending across the first diagonal and at least one receptacle contact substantially aligned with one of the receptacle openings. An electromechanical apparatus is disposed in the back body within a region substantially aligned with the substantially square area. The electromechanical apparatus includes a toroidal sensor assembly coupled to an actuator coil arranged along a center axis in substantial alignment with the first diagonal, the center axis forming an acute angle relative to a side wall of the back body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is application is a continuation-in-part of U.S. patent applicationSer. No. 13/608,675 filed on Nov. 19, 2012, the content of which isrelied upon and incorporated herein by reference in its entirety, andthe benefit of priority under 35 U.S.C. §120 is hereby claimed, U.S.patent application Ser. No. 13/608,675 claims priority under to U.S.Provisional Patent Application No. 61/635,432 filed on Apr. 19, 2012,the content of which is relied upon and incorporated herein by referencein its entirety, and the benefit of priority under 35 U.S.C. §119(e) ishereby claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to electrical wiring devices,and particularly to electrical wiring devices that include electriccircuit protective features.

2. Technical Background

The average consumer is so used to having electric power at his beckoncall, that he often forgets, or does not know, how that electric poweris delivered to him. The terms “electrical wiring device” or “electricalcircuit” are thus very often abstractions to the typical consumer. Assuch, it may be useful to provide a brief review of the terminology thatis used to describe the technologies related to the delivery of electricpower within a structure or a residence.

AC electric power service provided by the power utility is usuallyterminated by a breaker panel located within the residence. Very oftenthe breaker panel is disposed in the basement of the structure if it hasone. The breaker panel distributes the electric power to various branchcircuits throughout the structure such that each branch circuit ismonitored and controlled by a circuit breaker. If the circuit breakerdetects a fault condition it will trip the breaker to interrupt thedelivery of power to that circuit. Moreover, the consumer may manuallyactuate the breaker switch to interrupt the delivery of power to thatcircuit. The breaker switches may be rated at 20A or 15A depending onthe nature of the branch circuit.

The backbone of a single phase branch circuit typically includes a cablethat has a black (hot) wire, a white (neutral) wire and a green (ground)wire. In some cases, only two wires (hot and neutral) are employed. Anadditional hot wire is required for each additional phase such that atwo phase circuit may include four wires and a three phase circuit mayinclude five wires. The conventional method for installing electricalcircuits includes a “rough-in” installation phase and a finishinstallation phase. In the rough-in phase, conduit or cable is disposedthroughout the structure in accordance with the building plans. Junctionboxes are installed at appropriate locations to house electricalconnection points where two or more conductors can be spliced together.Device boxes are installed throughout the structure where electricalservice is desired. After the boxes are placed, the electrical wires arepulled through the conduits (if provided) and all of the circuits arebonded such that the neutral conductors are connected to ground at ornear the circuit breaker.

The electrical wiring in a branch electric circuit typicallyinterconnects one or more electrical wiring devices. One or moreelectrical wiring devices may be mounted to a device box depending onthe size of the device box. A single-gang device box typicallyaccommodates one electrical wiring device; a two-gang device box willtypically accommodate two electrical wiring devices, and so on and soforth. An electrical wiring device provides the consumer with a point ofaccess to electrical service. For example, a receptacle outlet providespower to a portable device when the device's corded power plug isinserted into an energized receptacle. Once an electrical wiring deviceis installed inside the device box, a cover plate is disposed over theelectrical wiring device to “complete the electrical enclosure” suchthat individuals are not exposed to “hot” electrical wiring after theelectrical power is turned ON.

From a structural standpoint, an electrical wiring device is disposedwithin an electrically non-conductive housing, and nowadays thatnon-conductive material is usually made from a hard plastic material. Aset of line terminals, a set of load terminals and often a groundconnection are provided at the exterior of the electrical wiring deviceand are connected to electrical components or conductors disposed in theinterior of the device. The “line terminals” of an electrical wiringdevice refers to the terminals that connect the wiring device toconductive wires from the breaker panel. The “load terminals” or the“feed-through load terminals” are connected to downstream wiring that isconfigured to propagate AC power to one or more downstream electricalloads. The term “receptacle load terminals” refers to a receptacleoutlet that provides power to a portable load when a corded power plugis inserted therein. A load, of course, refers to an appliance, alighting device, or some other kind of device that consumes electricalpower during operation.

Certain types of electrical faults are known to occur in branch electriccircuits and electrical wiring systems. These faults represent serioussafety issues that may result in fire, shock or electrocution if notaddressed properly. Electric circuit protection devices are deployed inthe branch electric circuits to prevent the consumer from being shockedor electrocuted when such faults occur. These protective devices usuallyinclude a circuit interrupter disposed between the line terminals andthe load terminals. The circuit interrupter provides power to the loadterminals under normal conditions; however, when the protective devicedetects a fault condition in the load circuit, it will trip the circuitbreaker to interrupt electrical connectivity between the line terminalsand the load terminals. There are many types of electric circuitprotection devices including ground fault circuit interrupters (GFCIs),arc fault circuit interrupters (AFCIs), transient voltage surgesuppressors (TVSSs), or surge protective devices (SPDs). This listincludes representative examples and is not meant to be exhaustive and asingle device may be configured to perform one or more of thesefunctions (e.g., a combination AFCI/GFCI).

There are several drawbacks associated with conventional installationmethods and conventional protective electrical wiring devices.Conventional protective electrical wiring devices often do not makeefficient use of space. In addition, mounting the wiring device's groundstrap to the device box is tedious, time consuming, and thereforecostly. The same can be said of mounting the cover plate to theelectrical wiring device. Moreover, in multi-gang installations, thefinished look is often ragged because the plurality of electricaldevices and their respective cover plates are typically not inalignment. This misalignment can be, and very often is, in all threedimensions. Retrofitting an electrical installation can also beproblematic from the standpoint of the finished look because the devicebox, or an old work box, may not be precisely aligned to the plane ofthe wall surface. This is especially true if the wall surface itself isuneven. After remodeling a space, homeowners often seek to replace anexisting wall plate with one that better matches the new décor. Thus, ahomeowner may inadvisably remove the faceplate cover from an energizedwiring device and inadvertently become exposed to a shock hazard fromthe “hot” electrical wiring.

What is needed therefore is a protective electrical wiring device systemthat addresses the drawbacks articulated above. In particular, what isneeded is a protective electrical wiring device that may be employed ina number of different form factors without having to modify the internalelectro-mechanical configuration of the device. Stated differently, aprotective device is needed that can be configured in a conventionalform factor or in another form factor suitable for use in a modularframing system such that it does not require fasteners to be securelyinstalled within the device box.

SUMMARY OF THE INVENTION

The present invention addresses the needs described above by providing aprotective electrical wiring device system that addresses the drawbacksarticulated above. The protective electrical wiring device of thepresent invention may be employed in a number of different form factorswithout having to modify the internal electro-mechanical configurationof the device. In other words, the protective device of the presentinvention can be configured in a conventional form factor or in a formfactor suitable for use in a modular framing system such that it doesnot require fasteners to be securely installed within the device box. Inone embodiment of the present invention, the protective device isprovided in one or more modular embodiments that are employed within arigid frame that “completes the enclosure.” Because the frame of thepresent invention completes the enclosure, it may be employed with newconstruction, old construction or retrofits. The frame can support avariety of modular electrical wiring devices of differing sizes. Asexplained below, the modular protective wiring device of the presentinvention may be configured to be mounted to the frame instead of thedevice box such that fasteners are not required for installation withinthe device box. In the modular embodiment, no cover plate is neededbecause the frame completes the enclosure, and therefore, the coverplate is replaced by an aesthetic overlay that can be removed at anytime without exposing the homeowner to shock or electrocution.

As its name suggests, the aesthetic overlay of the present invention maybe comprised of a variety of decorator materials without regard to thestructural considerations that are concomitant with completing theenclosure. Thus, the modular protective device may be provided in anumber of modular form factors to optimize the decorative impact of thesystem. Accordingly, the protective electrical wiring device of thepresent invention may present either a two-module or a three-modulefront cover depending on the aesthetics of the design. In a multi-gangconfiguration, for example, the form factor of the protective electricalwiring device may be selected to match module size of the otherelectrical devices within the multi-gang device box such that theyconveniently fit within a single aesthetic overlay in perfect alignmentin all three dimensions. The present invention may also be adapted to aconvention wiring device form factor.

One aspect of the present invention is directed to a protective devicethat includes a plurality of line terminals, a plurality of feed-throughload terminals and a ground connection element accessible via a backbody. A cover assembly includes a plurality of receptacle openings, areset button and a test button. The reset button and the test button aredisposed along a first diagonal and in opposite corners of asubstantially square area defined by the reset button and test button.At least one receptacle contact structure includes a portion extendingacross the first diagonal and at least one receptacle contactsubstantially aligned with one of the receptacle openings. Anelectromechanical apparatus is disposed in the back body within a regionsubstantially aligned with the substantially square area. Theelectromechanical apparatus includes a toroidal sensor assembly coupledto an actuator coil arranged along a center axis in substantialalignment with the first diagonal, the center axis forming an acuteangle relative to a side wall of the back body. The actuator coilprovides an actuation stimulus in response to a detected faultcondition. A circuit interrupter is configured to render the pluralityof line terminals, the plurality of feed-through load terminals and theat least one receptacle contact structure electrically discontinuous inresponse to the actuation stimulus and electrically continuous inresponse to an actuation of the reset button.

In another aspect, the present invention is directed to an electricalwiring system that includes a frame assembly configured to be mounted toa device wall box installed in a structure. The frame includes a firstedge formed around a peripheral portion of the frame, the first edgebeing configured to abut a structural surface disposed around the devicewall box. The frame assembly includes a ground portion configured toprovide a ground path from the frame assembly to ground. The frameassembly further includes a frame opening corresponding to at least onegang opening. The frame opening substantially defines a second edgeconfigured to extend inwardly toward the device wall box interior suchthat the frame opening provides sole access to the device wall boxinterior. A protective device is configured to snap-mount within theframe opening. The protective device includes a plurality of lineterminals, a plurality of feed-through load terminals and a groundconnection element accessible via a back body. A cover assembly includesa plurality of receptacle openings, a reset button and a test button.The reset button and the test button are disposed along a first diagonaland in opposite corners of a substantially square area defined by thereset button and test button. At least one receptacle contact structureincludes a portion extending across the first diagonal and at least onereceptacle contact substantially aligned with one of the receptacleopenings. An electromechanical apparatus is disposed in the back bodywithin a region substantially aligned with the substantially squarearea. The electromechanical apparatus includes a toroidal sensorassembly coupled to an actuator coil arranged along a center axis insubstantial alignment with the first diagonal, the center axis formingan acute angle relative to a side wall of the back body. The actuatorcoil provides an actuation stimulus in response to a detected faultcondition. A circuit interrupter is configured to render the pluralityof line terminals, the plurality of feed-through load terminals and theat least one receptacle contact structure electrically discontinuous inresponse to the actuation stimulus and electrically continuous inresponse to an actuation of the reset button. An aesthetic overlay isconfigured to be removably coupled to the frame assembly, the aestheticoverlay including an overlay opening configured to provide access to atleast a portion of the cover assembly.

Additional features and advantages of the invention will be set forth inthe detailed description which follows, and in part will be readilyapparent to those skilled in the art from that description or recognizedby practicing the invention as described herein, including the detaileddescription which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary of theinvention, and are intended to provide an overview or framework forunderstanding the nature and character of the invention as it isclaimed. The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate various embodimentsof the invention and together with the description serve to explain theprinciples and operation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a protective wiring system in accordancewith one embodiment of the present invention;

FIGS. 2A and 2B are perspective views of the frame member depicted inFIG. 1;

FIG. 3 is a perspective view of the protective wiring device depicted inFIG. 1;

FIG. 4 is a perspective view of a protective wiring device in accordancewith an alternate embodiment of the present invention;

FIG. 5 is a perspective view of the protective wiring device depicted inFIG. 3 with the front cover assembly removed;

FIG. 6 is a first perspective view of the protective wiring devicedepicted in FIG. 3 with the housing assembly removed;

FIG. 7 is a second perspective view of the protective wiring devicedepicted in FIG. 3 with the housing assembly removed;

FIG. 8 is a perspective view of the protective wiring device depicted inFIG. 3 with the housing assembly and the separator cap removed;

FIG. 9 is a perspective view of the protective wiring device depicted inFIG. 3 with the housing assembly, separator and separator cap removed;

FIG. 10 is a perspective view of a protective wiring system inaccordance with another embodiment of the present invention;

FIG. 11 is a perspective view of a protective wiring device depicted inFIG. 10;

FIG. 12 is a perspective view of the protective wiring device depictedin FIG. 10 with the front cover assembly removed;

FIG. 13 is a perspective view of the protective wiring device depictedin FIG. 10 with the housing assembly and the separator cap removed;

FIG. 14 is a perspective view of the protective wiring device depictedin FIG. 10 with the housing assembly, separator and separator capremoved;

FIG. 15 is another perspective view of the protective wiring devicedepicted in FIG. 10 with the housing assembly, separator and separatorcap removed;

FIG. 16 is a rear perspective view of the protective wiring devicedepicted in FIG. 10;

FIG. 17 is a perspective view of the printed circuit board assembly ofthe protective wiring device depicted in FIG. 10;

FIG. 18 is a perspective view of the lower latch block assembly depictedin FIG. 17;

FIG. 19 is a perspective view of the latch block assembly in accordancewith another embodiment of the present invention;

FIG. 20 is a perspective view of the lower latch block portion of thelatch block assembly depicted in FIG. 19;

FIG. 21 is a perspective view of a protective wiring device inaccordance with yet another embodiment of the present invention;

FIG. 22 is a schematic view of a ground fault circuit interrupter inaccordance with embodiments of the present invention;

FIG. 23 is a schematic view of a ground fault circuit interrupter inaccordance with alternate embodiments of the present invention; and

FIG. 24 is a schematic view of an arc fault circuit interrupter inaccordance with yet other alternate embodiments of the presentinvention.

DETAILED DESCRIPTION

Reference will now be made in detail to the present exemplaryembodiments of the invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.An exemplary embodiment of the protective device of the presentinvention is shown in FIG. 1, and is designated generally throughout byreference numeral 10.

As embodied herein and depicted in FIG. 1, a perspective view of aprotective wiring system 100 in accordance with an embodiment of thepresent invention is disclosed. System 100 includes a protective wiringdevice 10 disposed within frame member 90. The protective device 10includes a front cover assembly 12 that is accessible via an opening90-13 of the frame. The back body portion 14 of the device 10 is snappedinto the frame 90 such that it is positioned within the device box (notshown). The back body portion 14 is inaccessible to the user once it iscoupled to the frame 90. Thus, one of the features of this embodiment ofthe present invention is that the frame member 90 is configured to“complete the electrical enclosure” when a modular electrical device(such as protective device 10) is properly installed within the frame90. The frame member 90 prevents individuals from being exposed to hotelectrical wiring in the device box.

Referring to FIGS. 2A and 2B, perspective views of the frame member 90depicted in FIG. 1 are disclosed. FIG. 2A is directed to the rear side90-2 of the frame member 90, whereas FIG. 2B is directed to the frontside 90-1 of the frame member 90. With respect to “completing theelectrical enclosure” when a modular electrical device is properlyinstalled within the frame, the modular device is snapped into frameopening 90-13 and completely fills the opening 90-13. In conventionaldesigns, a conventional wall plate is used to complete the enclosure. Asstated above, the present invention thus prevents individuals from beingexposed to hot electrical wiring in the device box before a wall plateis installed.

Note that a frame enclosure lip 90-5 is formed around the outerperimeter of the frame. The frame enclosure lip 90-5 is configured to bedisposed over, and abut, the wall surface 1 (not shown in this view).The edge of a properly installed wall box would thus seldom, if ever;touch the rear surface of the frame because of the frame enclosure lip90-5 provides separation between the frame and the wall surface. This istrue even when old work boxes are deployed. Old work boxes, of course,have flanges that mount to the outer surface of the sheet rock. One ofthe functions of the frame enclosure lip 90-5 is therefore to avoidinterference with these flanges such that the frame 90 does contact thewall surface 1.

The frame opening 90-13 is sized to accommodate three device modules.Stated differently, the frame opening can accommodate three one-moduledevices, a one module device and a two module device, or a three moduledevice. The frame 90 may be equipped with modular alignment connectorsthat allow the electrical enclosure to be completed with a singletwo-module sized device. In this case, the device is disposed betweentwo alignment connectors that together take up one module's worth ofspace within opening 90-13. Reference is made to U.S. patent applicationSer. No. 13/608,675, which is incorporated herein by reference as thoughfully set forth in its entirety, for a more detailed explanation of theframe member 90.

The frame opening 90-13 has edge portions that mate with the snapelements 14-4 (see FIG. 5) formed in the back body of the protectivewiring device 10 shown herein. The device depicted in FIG. 1, forexample, is equipped with a three-module sized back body 14 and a twomodule front cover 12. Thus, the device 10 does not require the use ofany modular alignment connectors. Again, once the electrical wiringdevice is installed within the frame opening 90-13, the enclosure iscompleted. An interior serrated lip 90-6 extends from both side portionsof the frame device opening 90-13 and adjoins a connector landingelement 90-7 disposed at either end of the frame opening 90-13. Theinterior serrated lips 90-6 and the connector landing elements 90-7extend perpendicularly around the entire frame opening 90-13 to form arim or skirt that is inserted into the device box during installation.Accordingly, the region between the outer enclosure lip 90-5 and theinterior rim (i.e., serrated lips 90-6 and landing 90-7) is disposedover the wall surface 1. Once the wall box fasteners 90-10 are insertedinto the fastener slots 90-12 and tightened, the only way of accessingthe interior of the device box is via the frame opening 90-13. However,the frame opening 90-13 is completely occupied by the protective wiringdevice 10 and thus the interior of the device box is inaccessible.

Referring to FIG. 3, a perspective view of the protective wiring device10 depicted in FIG. 1 is disclosed. Again, the protective device 10includes a two module front cover 12 and a three module back body 14.The front cover 12 includes stepped portions 12-1 that are recessedrelative to the raised center portion 12-2 formed in front cover 12. Theportion of the front cover 12 that includes the receptacle openings 16,test button 15 and reset button 17 is framed by an aesthetic overlay(not shown). Note that the reset button and the test button arediagonally disposed with respect to each other. Stated differently, asubstantially square area 11 is formed by extending imaginary horizontaland imaginary vertical lines from the outer edges of the test and resetbuttons such that the test and reset buttons are disposed in oppositecorners of the substantially square area 11. The term “imaginary lines”means that the lines are not visible on the device but are merely usedto define the meaning of the term “square area” herein. The stepped orrecessed cover portions 12-1 are hidden behind the aesthetic overlaywhen it is mounted to the frame to give the assembly a finished andaesthetically pleasing appearance. As described in U.S. patentapplication Ser. No. 13/608,675, which is incorporated herein byreference as though fully set forth in its entirety, the frame 90 isconfigured to retain an aesthetic overlay by way of ratcheting snapelements 90-3, 90-3′ and 90-4.

Note that the reset button 17 includes a visual indicator lens 17-1formed therein. The lens 17-1 is in optical communication with a lightsource disposed within the housing of device 10. The nature of theindicator is described below in the discussion of the variousschematics. The back body is shown herein to include snap elements 14-1which are configured to snap into and mate with the serrated edges 90-60of the frame opening 90-13.

Referring to FIG. 4, a perspective view of a protective wiring device inaccordance with an alternate embodiment of the present invention isdisclosed. Note that in the various views provided herein, likereference numerals refer to identical or functionally-similar elements.The device of FIG. 3 is a 15A device, whereas the device 10 of FIG. 4 isa 20A device, as shown by the neutral openings 16-2′ in FIG. 4.Otherwise, both devices are similar. FIG. 4 also shows self-groundingcontact 14-3, which is also employed in the 15A device of FIG. 3 (butnot shown). Alternatively, the ground connection may be made via aground wire 14-3′. Device 10 also includes line terminals 14-1 which areconfigured to terminate the wiring that extends back to the breakerpanel. Load terminals 14-2 (not shown in this view) are disposed at theopposite end of the device 10.

Referring to FIG. 5, a perspective view of the protective wiring devicedepicted in FIG. 3 (with the front cover assembly removed) is shown. Thedevice 10 includes a separator cap 20 that is disposed under the frontcover 12. The separator cap 20 is fabricated from a non-conductivematerial and is configured to accommodate the shutter assemblies 22 andthe ground strap 24. The test button 15 and the reset button 17 areconnected to components that are disposed under the separator cap 20.The ground strap 24 includes receptacle ground contacts 24-1 that arealigned with the ground prong openings 16-3 formed in the front cover12. Thus, when a corded plug is inserted into the receptacle openings16, the ground prong portion extends through opening 16-3 to mate withthe ground contacts 24-1. The movistor MOV1 is also seen in this view;MOV1 is connected to between the line terminals 14-1. Reference is madeto U.S. patent application Ser. No. 13/487,547, filed Jun. 4, 2012 whichis incorporated herein by reference as though fully set forth in itsentirety, for a more detailed explanation of the shutter assemblies 22.

Referring to FIG. 6, a first perspective view of the protective wiringdevice depicted in FIG. 3 is disclosed. This view shows the latch blockassembly 50, the hot circuit interrupter 60-1, and illustrates theunderside of the PCB 40 with the housing assembly removed.

Two different contact embodiments are shown at the same time forpurposes of comparison. The contacts (60-11, 60-12, 60-13) in the firstembodiment are referred to sandwiched contacts and can be said to be“in-line” (thus, 60-10 and 60-14 are not employed in this embodiment).In this embodiment, the hot side of the circuit interrupter 60-1includes a line hot contact arm 40-10 and a load hot contact arm 40-20.The line hot contact arm 40-10 includes a dual-sided contact 60-11 whichmates with the load hot contact 60-12, respectively, (disposed on theload hot arm 40-20) and the fixed hot load contact 60-13 when circuitinterrupter 60 is in the reset state. Contacts 60-11, 60-12, and 60-13share a common axis. The contacts are separated from one another whencircuit interrupter 60 is in the tripped state. Again, contacts 60-10and 60-14 are omitted in the first alternate embodiment.

In the alternate contact embodiment contacts 60-10 and 60-14 areincluded and contact 60-12 is omitted. Line contact 60-10 is connectedto line hot contact arm 40-10 and load hot contact 60-14 is connected toload hot arm 40-20. Contact 60-11 is still connected to the line hotcontact arm 40-10 but since hot line contact 60-12 is omitted it needonly be a single sided contact having only to mate with contact 60-13.When circuit interrupter 60 is in the reset state contacts (60-10,60-14) mate and contacts (60-11, 60-13) mate. Since contact pairs(60-10, 60-14) and (60-11, 60-13) lie on two axes this arrangement isreferred to as a “staggered contact” arrangement. In the tripped statecontacts (60-10, 60-14) and (60-11, 60-13) are separated.

The neutral side of circuit interrupter 60-2 includes a similararrangement. The circuit interrupter 60 is configured to work inconjunction with the latch block assembly 50, the reset pin assembly 17,and the fault detection apparatus disposed on PCB 40 to drive thecircuit interrupter 60 into the tripped state or the reset state. Thefault detection apparatus disposed on PCB 40 is described below in thediscussion of the schematic diagrams provided herein. (See, e.g., FIGS.22-24).

The latch block assembly 50 is shown to include an upper latch blockportion 52 and a lower latch block portion 54. The latch block 50 iscoupled to the reset button by way of reset pin 17-5. A break spring17-4 is disposed around the reset pin and exerts a break force duringthe tripping action. A make spring 50-1 is disposed between theseparator 30 and the latch block assembly 50. The make spring 50-1exerts a force against the latch block in the reset state to ensure thatthe contacts of the circuit interrupter 60 are closed and do not arc.

The lower latch block 54 is also coupled to an auxiliary switch KR1disposed at the underside of PCB 40. The plunger 54-1 extends from thelower latch block through an opening formed in PCB 40 to open theauxiliary switch KR1. Accordingly, the auxiliary switch KR1 operates inconjunction with the circuit interrupter such that when the circuitinterrupter is opened (i.e., device 10 is tripped), the auxiliary switchKR1 is opened, and vice-versa. The switch KR1 includes switch contactsKR1-1 disposed on either end of a conductive bus bar KR1-4 that make andbreak contact with switch contacts KR1-2 that are mounted on theunderside of the PCB 40. The switch contacts KR1-2 are, in turn,electrically connected to circuit traces formed in PCB 40 in accordancewith the present invention (See, e.g., the schematic of FIG. 22). SwitchKR1 is closed when the circuit interrupter is in reset state due tospring KR1-3 being compressed between the back body 14 and bus barKR1-4. In the tripped state, plunger 54-1 drives the bus bar to the openposition causing spring KR1-3 to compress further. The length of plunger54-1 is chosen to ensure contacts KR1-1 close before the contacts incircuit interrupter 60 close.

Referring to FIG. 7, a second perspective view 10-2 of the protectivewiring device 10 depicted in FIG. 3 is disclosed. FIG. 7 is rotatedrelative to the view of FIG. 6 such that the separator cap 20, showndisposed above the separator member 30, is more clearly visible. Notethat like reference numerals refer to identical or functionally-similarelements. FIG. 7 illustrates that the receptacle contact structures 30-1(hot) and 30-2 (neutral) are disposed within the separator member 30 andisolated from the ground conductor 24 by the separator cap 20. Thereceptacle contact structures (30-1, 30-2) drop into pockets formed inthe separator 30 and then held in place by the separator cap 20.

Referring to FIG. 8, a perspective view 10-3 of the protective wiringdevice 10 depicted in FIG. 3 is disclosed with the housing assembly andthe separator cap removed. Again, like reference numerals refer toidentical or functionally-similar elements. This view more clearly showsthe configuration of the hot receptacle conductor 30-1 and the neutralreceptacle conductor 30-2. The hot receptacle conductor 30-1 issubstantially “L-shaped.” The first leg of the hot receptacle contactstructure 30-1 extends along one side of the device in a longitudinaldirection (within the separator 30) between the movistor MOV1 and thereset button 17. The second leg extends from the intersection with thefirst leg across the device to the opposite side of the device. The linehot contact 60-11 of the hot side of the circuit interrupter 60-1 isformed where the latitudinal leg of the hot contact structure 30-1 meetsthe longitudinal leg of the contact structure 30-1. One set ofuser-accessible hot receptacle contacts 30-12 is formed at the free endof the longitudinal leg and the other set of user-accessible hotreceptacle contacts 30-12 is formed at the free end of the latitudinalleg. As such, the sets of hot receptacle contacts 30-12 are disposed“kitty-corner” at opposing corners of the device (See, e.g., FIG. 1).The neutral receptacle conductor 30-2 is substantially straight andextends approximately along the center longitudinal axis of the device10 within the separator 30. The neutral set of contacts 30-22 isprovided at each end of the neutral receptacle conductor 30-2.

Referring to FIGS. 8 and 9, the separator 30 also accommodates a testprinted circuit board (PCB) 15-1 that includes contact pads that areconnected to a first test wire lead 15-2 and a second test wired lead15-3 (not shown). The first test wire lead 15-2 is connected to the hotreceptacle conductor 30-1 and the second lead 15-3 is connected to thePCB 40. (See, e.g., FIG. 22). When the test button 15 is depressed bythe user, a conductive bus bar underneath the button bridges the contactpads formed on test PCB 15-1, closing the test switch. When test button15 is not depressed, a spring bias (not shown) between the button andPCB 15-1 keeps the test switch open.

Referring to FIG. 9, a perspective view 10-4 of the protective wiringdevice depicted in FIG. 3 is disclosed in accordance with an alternateembodiment of the invention. In this view, the housing assembly,separator and separator cap are removed. Once again, like referencenumerals refer to identical or functionally-similar elements. While manyof the components shown in this Figure have been described previously,the hot and neutral circuit interrupters (60-1, 60-2) are shown assandwiched contacts, one of the contact arrangements that have beendescribed already. Both this embodiment and the previous embodiment,however, are similar in layout. The line hot conductor 40-10 extendsdiagonally from the toroidal sensors L1/L2 (under the test button 15) tothe hot circuit interrupter 60-1 (substantially under the reset button17). The load hot terminal 14-20 is connected to the load hot conductor40-20 which extends along the longitudinal edge of PCB 40 before it isbent 180° backwards (in a u-shape) towards the circuit interrupter 60-1.Thus, the line hot conductor 40-10 and the load hot conductor 40-20 forman acute angle with the vertex being located at the circuit interrupter60-1. The line neutral conductor 40-12 also extends diagonally from thetoroidal sensors L1/L2 (under the test button 15) to the neutral circuitinterrupter 60-2 (substantially under the reset button 17). The loadneutral terminal 14-22 is connected to the load neutral conductor 40-22which extends latitudinally from the opposite edge of PCB 40 towards theneutral circuit interrupter 60-2. The line neutral conductor 40-12 andthe load neutral conductor 40-22 also form an acute angle, with thevertex being located at the neutral circuit interrupter 60-2. Thisstructure, along with that of the receptacle conductors (30-1, 30-2)allows the device 10 to conform to various form factors including thosedescribed herein.

As embodied herein and described in FIG. 10, a perspective view of aprotective wiring system 100 in accordance with another embodiment ofthe present invention is disclosed. This embodiment is like the firstembodiment in that the reset button and the test button are againdiagonally disposed with respect to each other such that the test andreset buttons are disposed in opposite corners of substantially squarearea. This modular embodiment differs from the one depicted in FIGS.1-9, in that the size of the front cover portion is increased from twomodules to three modules. The aesthetic cover plate (not shown) employedwith this embodiment will also require a three module sized opening,whereas the aesthetic plate opening in the previous embodiment is onlytwo modules in size. The consumer may select the three module device 10for any number of reasons including aesthetic ones.

Referring to FIG. 11, a perspective view of a protective wiring devicedepicted in FIG. 10 is disclosed. Once again, like reference numeralsrefer to identical or functionally-similar elements describedpreviously. As before, the front cover 12 includes receptacle openings16, test button 15 and reset button 17 and is framed by an aestheticoverlay that has a three module opening (not shown). This protectivedevice 10 differs from previous embodiments in that it includes a threemodule front cover 12 and a three module back body 14. The aestheticoverlay and frame member 90 are described in U.S. patent applicationSer. No. 13/608,675, which is incorporated herein by reference as thoughfully set forth in its entirety.

Another difference between this embodiment and the embodiment of FIGS.1-9 is that the orientation of the receptacle openings 16′ in thisembodiment are rotated 180° relative to the orientation of thereceptacle openings 16 in the previous embodiment (FIGS. 1-9). Stateddifferently, the ground prong openings are disposed along thelatitudinal edges of device 10, the neutral openings are disposed alongthe longitudinal edges and the hot blade openings are disposed in acentral region of the front cover 12.

Referring to FIG. 12, a perspective view 10-1 of the protective wiringdevice depicted in FIG. 10 is disclosed with the front cover assemblyremoved. The device 10 includes a separator cap 20 that is disposedunder the front cover 12 and over the separator 30. The separator cap 20is fabricated from a non-conductive material and is configured toaccommodate the shutter assemblies 22 and the ground strap conductor 24.The separator cap 20 of this embodiment is larger than the one employedin the previous embodiment and includes a flange portion 20-1 thataccommodates the ground contact 24-1 at one end and the self-groundingconnector 14-3 at the opposite end. The ground strap conductor 24includes receptacle ground contacts 24-1 that are aligned with theground prong openings 16-3 formed in the front cover 12. As describedpreviously, the self-grounding connector 14-3 is configured to contactframe 90 to thereby provide a path to ground.

As before, the test button 15 and the reset button 17 are connected tocomponents that are disposed under the separator cap 20. Reference ismade to U.S. Patent Application Ser. No. 13/487,547, filed Jun. 4, 2012which is incorporated herein by reference as though fully set forth inits entirety, for a more detailed explanation of the shutter assemblies22.

Referring to FIG. 13, a perspective view 10-2 of the protective wiringdevice depicted in FIG. 10 is disclosed with the housing assembly andthe separator cap removed. This view is similar to FIG. 8 in that itshows the hot receptacle conductor 30-1 and the neutral receptacleconductor 30-2 disposed within the separator 30. However, because thereceptacle openings 16 have been rotated 180° relative to that of theprevious embodiment, the relative positions and shapes of the hotreceptacle conductor 30-1 and the neutral conductor 30-2 are alsochanged vis á vis the previous embodiment. (Compare FIGS. 10-11 to FIGS.1-3). Accordingly, the hot receptacle conductor 30-1 extendssubstantially along the center longitudinal axis of the device 10(within the separator 30) such that the hot receptacle contacts 30-12are formed at each end thereof. The hot fixed contact 60-11 is connectedto a branch portion 30-11 that extends from a central portion of the hotconductor 30-1 toward the side of the device 10.

The neutral receptacle conductor 30-2, on the other hand, has a rathercomplex shape and includes a central leg 30-21 that extendslatitudinally from side-to-side within the separator 30. One set ofneutral receptacle contacts 30-22 extends longitudinally from one end ofthe central leg 30-21 towards the movistor MOV1. Another set of neutralreceptacle contacts 30-22 extends longitudinally from the other end ofthe central leg 30-21 away from the test button. A second neutral leg30-23 is shaped like the number seven (“7”). It includes a base portionthat extends from the central leg 30-21 and is disposed between theneutral receptacle contact set 30-22 and the hot receptacle contact set30-12. Thereafter, the second leg 30-23 includes two ninety degree turnssuch that it positions the neutral fixed contact 60-12 between the resetbutton and the hot receptacle contact set 30-12.

Like previous embodiments, the separator 30 accommodates the test PCB15-1 therewithin. The test wire 15-2 is connected to the hot receptacleconductor 30-1 and test wire 15-3 to the PCB 40.

Referring to FIG. 14, a perspective view 10-3 of the protective wiringdevice 10 depicted in FIG. 10 is disclosed. In this view, the housingassembly (12, 14), separator (30) and separator cap (20) are removedsuch that PCB 40 is shown in conjunction with the receptacle conductors30-1 and 30-2. The line hot conductor is shown to extend from thetoroidal sensors L1/L2 to form an acute angle relative to the load hotconductor 40-20. The hot receptacle branch conductor 30-11 is clearlyshown to extend from the hot receptacle conductor 30-1 such that thefixed hot contact 60-13 is disposed overtop line hot contact 60-11 andload hot contact 60-12. Except for the receptacle conductors (30-1,30-2), the components shown in FIG. 14 are the same as for the twomodule embodiment shown in FIG. 8.

FIG. 15 is another perspective view 10-4 of the protective wiring device10 depicted in FIG. 10. This view is rotated about ninety degreesrelative to the view provided by FIG. 14. Once again, like referencenumerals refer to identical or functionally-similar elements describedin the previous drawings. The housing assembly (12, 14), separator (30)and separator cap (20) are removed in this drawing. This view provides aclearer depiction of the neutral circuit interrupter 60-2 and the secondneutral leg 30-23 of the neutral receptacle conductor 30-2. Inparticular, the second neutral leg 30-23 is parallel to, and is disposedovertop, the neutral load conductor 40-22 such that the fixed neutralcontact 60-23, the line neutral contact 60-21 and the load neutralcontact 60-22 are in vertical alignment. In addition, the lineconductors 40-10 and 40-12 are clearly shown to extend diagonally acrossthe PCB 40 to form an acute angle relative to their respective loadconductors 40-20, 40-22. Spring 15-4 biases test button 15 in the openposition when not being depressed by the user.

Referring to FIG. 16, a rear perspective view of the protective wiringdevice depicted in FIG. 10 is disclosed. The line terminals 14-1 and theload terminals 14-2 provide wire insertion openings (14-100, 14-120,14-200, and 14-220) formed in the rear portion of the back body 14. Oncethe wires are inserted therein, the installer uses the screw terminalsformed in the ends of the back body to screw down a plate to prevent thewires from being pulled out of the wire insertion openings.

Referring to FIG. 17, a perspective view 10-5 of the printed circuitboard assembly of the protective wiring device depicted in FIG. 10 isdisclosed. Like reference numerals refer to identical orfunctionally-similar elements described previously. The line hotconductor 40-10 extends diagonally from the toroidal sensors L1/L2(under the test button 15) to the hot circuit interrupter 60-1(substantially under the reset button 17). The load hot terminal 14-20is connected to the load hot conductor 40-20 which extends along thelongitudinal edge of PCB 40 before it is bent 180° backwards towards thehot circuit interrupter 60-1. As before, the line hot conductor 40-10and the load hot conductor 40-20 form an acute angle with the vertexbeing located at the circuit interrupter 60-1. The line neutralconductor 40-12 also extends diagonally from the toroidal sensors L1/L2(under the test button 15) to the neutral circuit interrupter 60-2(substantially under the reset button 17). The load neutral terminal14-22 is connected to the load neutral conductor 40-22 which extendslatitudinally from the opposite edge of PCB 40 towards the neutralcircuit interrupter 60-2. The line neutral conductor 40-12 and the loadneutral conductor 40-22 form an acute angle with the vertex beinglocated at the neutral circuit interrupter 60-2. This structure, alongwith that of the receptacle conductors (30-1, 30-2) allows theelectro-mechanical design to conform to various form factors includingthose described herein.

The latch block 50 includes an upper latch block 52 and a lower latchblock 54 which are described in greater detail below. The latch block 50includes an upper latch block portion 52 and a lower latch block portion54. A central aperture 52-1 in the upper latch block portionaccommodates the reset pin 17-5. The upper latch block 52 furtherincludes breaker arms 52-2 which are configured to force the lineconductors 40-10, 40-12 downwardly during a tripping action to break thecontact between the fixed contacts 60-13, 60-23 (not shown in this view)and the line contacts (60-11, 60-21). In particular, upper breaker arms52-2 apply force to extension fingers 40-100 on line conductors (40-10,40-12.) Similarly, lower breaker arms 52-20 (not shown in this view)apply force to extension fingers disposed on load conductors(40-20,40-22) during a tripping action to break the contact between theline contacts (60-11,60-21) and the load contacts (60-12,60-22.) Inparticular, lower breaker arms 52-20 apply force to extension fingers onload conductors (40-20, 40-22.) The breaker arms 52-2 assure a positionof line conductors arms (40-10,40-12) and breaker arms 52-20 assure aposition of load conductors (40-10,40-12) in the tripped state. As such,the upper and lower breaker arms assure a predetermined minimumseparation distance between line contacts (60-11,60-21) and loadcontacts (60-12,60-22) when circuit interrupter 60 is in the trippedstate. Note that the extension fingers on the load conductors are notvisible in this view, but are similar to the extension fingers 40-100provided on the line conductors.

The lateral portions of the solenoid bobbin assembly 70 are disposedbetween the line conductor arms (40-10, 40-12) while its end portionsare positioned between the toroidal assembly L1/L2 and the latch blockassembly 50. The overall length of the toroidal assembly L1/L2, bobbinassembly 70 and latch block assembly 50 can be greater than the distancebetween the line terminals (14-10,14-12) and the load terminals(14-20,14-22) since they are mounted to PCB 40 along a diagonal axis.The movistor MOV1 (shown in FIG. 15) is not depicted in this view forsake of clarity, but is connected between the line terminals 14-10 and14-12.

As embodied herein and depicted in FIG. 18, a perspective view of thelower latch block assembly 54 shown in FIG. 17 is disclosed. The lowerlatch block 54 includes a central body 54-6 having a central aperture54-3 formed therein. The central aperture 54-3 accommodates the resetpin 17-5 which extends through an opening in the latch member 56 in thereset state. The central body portion 54-6 also includes a side opening54-5 that is configured to accommodate the lower portion of the U-shapedlatch member 56 (not shown). The side opening 54-5 includes rails 54-50that allow the lower portion of the latch 56, which is inserted intoopening 54-5, to slide back and forth between the tripped state and thereset state. The latch 56 also includes arms 56-2 that extend around thecentral opening 54-3. The arms 56-2 include a catch that engages astepped retainer portion of the central body 54-6. The catch and steppedportion resist the force applied by spring 58 to hold the latch inplace. The latch spring 58 tends to force the latch member away from thecentral body 54-6 when no other stimulus is applied. When reset button17 is depressed and released, the lower portion of latch 56 is liftedtoward the central body 54-6 by reset pin 17-5 due to the bias of makespring 50-1. The upward motion of latch 56 in turn lifts lower latchblock assembly 54 to the reset position by way of lifter arms 54-2. Inparticular, the lifter arms 54-2 lift the load arms (40-20, 40-22) whichin turn lift the respective line arms (40-10, 40-12) upwardly such thatthe circuit interrupters 60-1 and 60-2 are reset. Conversely, when thedevice is tripped, the solenoid armature 70-1 (not shown) engages thefront plate 56-1 of the latch 56 to compress the latch spring 58. Thisaction releases the reset pin 17-5 from the latch and causes the lowerlatch block 54 to drop such that the circuit interrupters 60-1 and 60-2are opened (tripped).

As described previously, the central body 54-6 also includes a plunger54-1 that extends into an opening formed in the PCB 40. When the circuitinterrupter 60 is in the tripped state, the plunger 54-1 engages theauxiliary switch KR1 such that it is open. When the circuit interrupter60 is in the reset state, the plunger 54-1 is retracted such that theauxiliary switch KR1 is closed. See, e.g., FIGS. 6 and 22.

Referring to FIG. 19, a perspective view of the latch block assembly 50′in accordance with another embodiment of the present invention isdisclosed. Again, like reference numerals refer to identical orfunctionally-similar elements described previously. In this embodiment,central apertures are substantially eliminated from both the lower latchblock 54′ and the upper latch block 52′. The upper latch block 52′ andthe lower latch block 54′ include central rectangular shaped voids 52-1and 54-3, respectively. The lower latch block 54′, however, does includean opening 54-6 in the bottom portion that aligns with the openingformed in the latch plate 56′.

As previously described herein, each side of the upper latch block 52′includes an upper arm 52-2 and a lower arm 52-20. As more clearly shownin this figure, the line conductors (40-10, 40-12) and load conductors(40-20,40-22) are not cantilevered per se; rather they are drivenbetween the reset and tripped positions respectively by arms(52-2,52-20) and arms 54-2. The positions of the line and load contacts(60-10, 60-11, 60-12, 60-22, 60-21, 60-23) thus rely on arms (52-2,52-20, 54-2) for positioning.

FIG. 20 is a perspective view of the lower latch block portion 54′ ofthe latch block assembly 50′ depicted in FIG. 19. Again, like referencenumerals refer to identical or functionally-similar elements describedpreviously. This embodiment employs an L-shaped latch 56′ rather thanthe U-shaped latch used in the previous embodiment.

As embodied herein and depicted in FIG. 21, a perspective view of aprotective wiring device 10 in accordance with yet another alternateembodiment of the present invention is disclosed. In this embodiment,the device is configured as a conventional wiring device that includesmounting ears 14-4′ instead of snaps that engage frame 90 (See, e.g.,FIG. 1). Moreover, the line terminals 14-1 and the load terminals 14-2are disposed along the sides of the back body 14 rather than in themanner previously described. However, this embodiment is like the firstembodiment in that the reset button and the test button are againdiagonally disposed with respect to each other such that the test andreset buttons are disposed in opposite corners of substantially squarearea. Thus, this embodiment may employ any of the electromechanicaldesigns described herein. The electromechanical arrangement describedpreviously allows the device to be configured in a variety of formfactors including those shown herein. Stated differently, the presentinvention provides an efficient and cost effective way to employ a givendesign within a variety of form factors.

As embodied herein and depicted in FIG. 22, a schematic view of theprotective circuit employed in the electrical wiring device of thepresent invention is disclosed. Moving from left to right in theschematic, it is seen that protective circuit 40 includes hot lineterminals 40-10 and a neutral line terminal 40-12. On the load side ofdevice 10, there is a pair of user accessible receptacles, eachincluding a hot receptacle terminal 30-12 and a neutral receptacleterminal 30-22. The load terminals include load hot terminal 14-20 andload neutral terminal 14-22.

The ground fault circuitry 400 includes a differential transformer L1which is configured to sense load-side ground faults. Transformer L2 isconfigured as a grounded neutral transmitter and is employed to sensegrounded-neutral fault conditions. Both transformers are disposed intoroid assembly L1/L2 described previously. Both differentialtransformer L1 and grounded-neutral transformer L2 are coupled to thefault detector integrated circuit 406. Detector 406 is powered by apower supply circuit 408 connected to pin V⁺ on detector 406. Thedetector 406 output, provided on output pin SCR, is connected to thecontrol input of SCR 410. Low pass filter 412, comprising resistor R10and capacitor C7, filter the detector output signal. GFCI 400 alsoincludes a snubber circuit 414 that includes resistor R4 and capacitorC8. Snubber circuit 414 prevents voltage transients from triggering SCR410.

When SCR 410 is turned ON, solenoid 70 is energized, actuating circuitinterrupter 60. Solenoid 70 remains energized for a time period that istypically less than about 25 milliseconds. Circuit interrupter 60 trips,resulting in the line terminals 14-1 being disconnected from respectiveload terminals 14-2. After the fault condition has been eliminated, thecircuit interrupter 60 may be reset by way of reset button 17. In oneembodiment, the reset mechanism 17 is purely mechanical in nature anddoes not include any electrical contacts for test initiation.

GFCI 400 addresses certain end of life conditions by denying power tothe load when the device is unable to function. As an example of anend-of-life condition, solenoid 70 is susceptible to burn-out if SCR 410becomes shorted out, or is permanently turned ON. Solenoid 70 may burnout if it is energized for more than about 1 second. Once the solenoid70 burns out, the circuit interrupter 60 is incapable of being tripped.Solenoid burn-out prevention is provided by auxiliary switch 422 (KR1).Auxiliary switch 422 is configured to open when the circuit interrupter60 is in the tripped position. If SCR 410 is shorted out or permanentlyON, auxiliary switch 422 ensures that solenoid 70 is not permanentlyconnected to a current source. The user may attempt to reset the device10 by depressing the reset button 17, but the circuit interrupter 60will immediately trip in response to the current flowing through thesolenoid 70. Because the latch block 50 is coupled to the auxiliaryswitch 422 by plunger 54-1, auxiliary switch 422 is opened beforesolenoid 70 can be burned out.

In another embodiment, another failure mode is addressed by GFCI 400;this mode relates to the end-of-life failure mode of movistor MOV1. MOV1 is disposed in series with auxiliary switch 422 and trip solenoid 70.This arrangement significantly reduces the probability of damage due toan over-current situation. When MOV 1 reaches end-of-life and shortsout, trip solenoid 70 is energized and auxiliary switch 422 is opened.As previously described, when auxiliary switch 422 opens, the flow ofshort circuit current is terminated before any damage to device 10ensues.

GFCI 400 also includes trip indication circuit 426. Trip indicator 426is implemented by placing LED1 and series resistors (R11-R14) inparallel with auxiliary switch 422. LED 1 is configured to emit a visualsignal when circuit interrupter 60 and auxiliary switch 422 are in anopen state (tripped). In an alternate embodiment LED 1 is replaced by anannunciator that provides an audible signal when interrupter 60 is inthe tripped state.

GFCI 400 also includes a test circuit 150. The test circuit 150 iscoupled between the line neutral terminal 14-12 and the hot receptacleterminal 30-12. The test circuit 150 includes a test button assembly 15shown here to include a switch disposed in series with test resistor R1.

As embodied herein and depicted in FIG. 23, a schematic view of a groundfault circuit interrupter 400 in accordance with another embodiment ofthe present invention is disclosed. Again, like reference numerals referto identical or functionally-similar elements. The instant embodimentincludes universal auto-test and indicator functionality that is notpresent in the previous embodiment.

As before, the ground fault circuitry 400 includes a differentialtransformer L1 which is configured to sense load-side ground faults,i.e. ground faults located in loads connected to load terminals 14-2 orreceptacle contacts (30-12, 30-22) and transformer L2, which isconfigured as a grounded neutral transmitter that is configured to sensegrounded-neutral fault conditions. Both transformers are disposed intoroid assembly L1/L2 as described above. Both differential transformerL1 and grounded-neutral transformer L2 are coupled to the fault detectorintegrated circuit 406. Detector 406 receives power from a dual powersupply circuit 408 that is described in greater detail below. The outputof the detector 406 is connected to the control input of SCR 410. WhenSCR 410 is turned ON, the dual-solenoid 70′ is energized to actuate thecircuit interrupter 60 such that the circuit interrupter 60 and theauxiliary switch 422 are tripped (opened). Solenoid 70′ remainsenergized for a time period that is typically less than about 25milliseconds. When the circuit interrupter 60 trips, the line terminals14-1 are disconnected from their respective load terminals 14-2 orreceptacle contacts (30-12, 30-22.) After the fault condition has beeneliminated, the circuit interrupter 60 may be reset by way of resetbutton 17 which has been depicted and described previously.

As its name suggests, the grounded neutral transmitter L2 is configuredto detect a grounded neutral condition. As an initial point, note thatthe line neutral conductor (i.e., the conductor that is connected toneutral line terminal 14-12) is typically grounded in the electricalcircuit at the panel—this does not constitute a grounded neutral faultcondition. When a grounded neutral condition is not present, thegrounded neutral transmitter L2 is configured to couple equal signalsinto the hot and neutral conductors. Because the differentialtransformer L1 is configured to sense a current differential, the equalsignals provided by grounded neutral transmitter L2 effectively canceleach other out. On the other hand, a grounded neutral condition doesoccur when the load neutral conductor (i.e., the conductor that isconnected to load neutral terminal 14-22 or neutral receptacle contact30-22) is accidentally grounded. This creates a parallel conductive path(relative to the neutral return path) between the neutral line terminal14-12 and neutral load terminal 14-22. As a result, another signalcirculates around this current loop and it is coupled onto the neutralconductor (but not the hot conductor) to create a differential current.The differential transformer L1 senses the differential current betweenthe hot and neutral conductors and the detector 406 generates a faultdetection signal in response thereto. The fault detection signal tripsthe circuit interrupter 60.

In reference to the dual power supply circuit 408, it is provided toaccommodate the needs of both the detection function (described above)and the universal auto-test circuit 401 described below. Dual supply 408includes power supply portion 408-1 which includes diode D1 in serieswith resistors R6 and R7. The series circuit is disposed between thecathode of diode D4 and the anode of diode D6. The power supply portion408-1 is thus connected to line hot via diode D4 and solenoid 70′ and isfurther configured to provide power to the supply terminal of detector406 via diode D6. Diode D4 is further connected to power supply portion408-2 which includes diode D2 in series with resistors R8 and R10; theseries circuit is connected to the cathode of diode D6. Power supplyportion 408-2 is configured to charge capacitor C6 whereas power supplyportion 408-1 is configured to charge the parallel capacitor bank 408-3(C16-C20). The total capacitance in bank 408-3 is greater than that ofcapacitor C6. The capacitor bank 408-3 has enough stored energy tomaintain the power supply voltage during the negative half cycleauto-test. When the AC line cycle is negative, the diode D6 is forwardbiased, thereby coupling capacitor bank 408-3 to capacitor C6. Becausethe power supply is active during the negative half cycle, detector 406is responsive during the auto-test.

When the GFCI 400 detects a fault condition, it is configured tointerrupt the circuit interrupter 60 during the positive half-cycle ofthe AC line cycle. In order to meet the trip time requirements, powersupply portion 408-2 is configured to charge to the full supply voltagein less than about 2 milliseconds. This means that during the positivehalf cycles, a hazardous ground fault condition is detected andinterrupted quickly. On the other hand, power supply portion 408-1 takeslonger to come up to full charge due to the large value of capacitorbank 408-3. Power supply portion 408-1 charges with a time constant thatis approximately 15 milliseconds. However, due to reverse biasing ofdiode D6, power supply portion 408-2 is not prevented from chargingquickly. In summary, detector 406 relies on power supply 408-2 duringthe positive half cycles for ground fault detection and relies on powersupply 408-1 for auto-testing during the negative half cycles.

At this point, it is helpful to bring the universal auto-test circuit401 into the discussion since one of the purposes of the dual powersupply 408 is to support the auto-test circuit 401. The auto-testcircuit 401 generates a simulated grounded neutral test signal by way ofwire loop 402 when FET (Q2) is turned ON. When FET 404 (Q2) is turnedON, the grounded neutral transmitter L2 produces an oscillating signalthat is a function of the full power supply voltage. The ON stateresistance of FET 404 is less than about 4 Ohms Thus, the wire loop 402,in combination with the FET 404 (in the ON state), forms a loop thatpasses through the differential transformer L1 and neutral transmitterL2 to simulate a grounded neutral condition. In an alternate embodiment,instead of having a third wire passing through the transformers (L1, L2)the wire loop 402 may incorporate a portion of the neutral conductorthat is disposed between line neutral terminal 14-12 and load neutralterminal 14-22. One advantage for placing the third wire within the wireloop relates to improved noise immunity. When the third wire isemployed, the wire loop 402 and the neutral conductor are isolated suchthat the current propagating in wire loop 402 during the self-test isnot affected by voltage drops or electrical noise propagating in theneutral conductor. Noise propagating on the neutral conductor couldotherwise impair the test fault signal and its detection by the GFCI.

The timing of the FET ON state is controlled by the timing resistor R14.In one embodiment of the present invention, the FET 404 is turned ONnear the conclusion of the positive half cycle of the AC power sourceand remains ON through a portion of the negative half cycle to producethe test fault signal. The grounded neutral transformer L2 generates adifferential current in response to the test current propagating in wireloop 402. The differential current is, in turn, sensed by transformerL1. If the circuit is working properly, the sensor signal provided by L1should be deemed by detector 406 as a fault. As described above, duringnormal operations and when the GFCI 400 is operating properly, the faultdetector 406 provides a fault detection signal that is sufficient toturn SCR 4100N. However, the auto-test is performed during the negativehalf cycle or late in the positive half cycle such that SCR 410 will notbe turned ON during the positive half cycle at a time that could causenuisance tripping of the circuit interrupter. In one embodiment, SCR 410is turned ON late in the positive half-cycle of the AC line cycle wherethe amount of current flowing through the SCR 410 is not sufficient toenergize the dual-solenoid 70′. In another embodiment, SCR 410 is turnedON during the negative half cycle, remaining ON until power supply 408is sufficiently discharged before the next positive half cycle, thatoccurring before the start of the next positive half cycle. Moreover,SCR 410 is prevented from conducting current through dual-solenoid 70′during the negative half cycle by diode D4.

One reason for using a relatively lengthy time duration for thesimulated fault signal generated by loop 402 is to ensure that detector406 has sufficient time to detect the self-test. One drawback to thisapproach relates to the duration of the magnetic flux in the sensorcore. Specifically, if the magnetic flux in the core carries over intothe subsequent positive half cycle, the resultant sensor output wouldcause detector 406 to improperly turn SCR 4100N and nuisance trip thedevice 10. For this reason, the output voltage of the dual power supply408 is collapsed before the conclusion of the negative half cycle. Onereason why the collapsible power supply voltage prevents nuisancetripping relates to the inability of grounded neutral oscillations topersist in the absence of the power supply output voltage. Even when FET404 is turned ON, there is substantially no magnetic flux in the sensorcore once the power supply voltage collapses. Thus, if the power supplyvoltage is collapsed before the conclusion of the negative half cycle,the grounded neutral oscillations that otherwise would be generated byFET 404, cannot carry over into the positive half cycle. Thus, the dualpower supply 408 prevents nuisance tripping.

The nuisance tripping prevention feature is now described in greaterdetail. During the self-test, FET 404 is turned ON and the groundedneutral transmitter 102 (L2) produces an oscillating signal that is afunction of the full power supply voltage. If the detector 406 isoperational, SCR 410 is turned ON at about 225°-280° of the AC linecycle (i.e., during a portion of the negative half cycle). As a result,capacitor C6 and capacitor bank 408-3 (by way of resistor R13,opto-coupler U2, and diode D5) are dump-discharged via SCR 410 tothereby collapse the output voltage of the power supply. The dischargingprocess occurs gradually because of the time constant associated withcapacitor bank 408-3. As the power supply voltage gradually collapses inaccordance with the aforementioned time constant, the magnitude of theoscillating signal produced by the grounded neutral transmitter L2 alsodiminishes. In turn, the grounded neutral simulation current propagatingaround loop 402 is also reduced. Finally, the flux in the transformercore is so low that the sensor signal it provides to the fault detector406 does not represent a fault condition. The above stated processtranspires before the conclusion of the negative half cycle.Accordingly, little or no flux is present in the transformer core at thestart of the subsequent positive half cycle. In one embodiment of thepresent invention, the capacitor bank 408-3 time constant is about 0.5milliseconds and the period of the grounded neutral oscillation is about0.15 milliseconds.

As noted above, SCR 410 turns on during the negative half cycle, howevercurrent through SCR 410 is prevented from conducting throughdual-solenoid 70′ during the negative half cycle because diode D4 isreverse biased. Watchdog circuit 421 monitors whether SCR 410 is turnedON or not, and it functions as follows: When SCR 410 turns ON indicativethat GFCI 400 is operational, power supply 408 discharges via resistorR13, the diode portion of opto-coupler U2, diode D5, and SCR 410.Because of the current through its diode portion, the transistor portionof opto-coupler U2 turns ON to discharge the watchdog capacitor C12.Stated differently, the negative half—cycle test is performed every ACline cycle such that the charge accumulated on C12 should be dischargedevery line cycle. However, when there is an end of life condition, SCR410 or opto-coupler U2 will fail to turn ON. If there is failure to turnon within four or five line cycles, the voltage on C12 becomes greaterthat the breakover voltage of diac Q3 and Q3 will conduct to turnopto-coupler U3 ON. The transistor portion of U3 is connected to thecontrol input of secondary SCR Q4, and therefore, when U3 conducts, SCRQ4 is turned on such that the secondary side of the dual-solenoid 70′ isenergized to trip the circuit interrupter 60 and the auxiliary switch422. In other words, if the self-test performed by universal auto-testcircuit 401 fails for a predetermined period of time, the watchdogcircuit 421 will trip the device 10.

A wiring state detection circuit 420 is configured to prevent miswiringupon initial installation. Detection circuit 420 includes resistors R9,R15, and fusible element 51. When power is initially applied to the loadterminals 14-20, 14-22 and the protective device is reset, theinterrupting contacts 60 are tripped within about 25 millisecondsbecause detection circuit 420 creates an imbalance in the differentialcurrent flowing through sensor L1. The imbalance is detected by detector406, SCR Q1 is turned ON and the device is tripped in the mannerdescribed above. Once AC power is properly connected the line terminals14-10, 14-12, the fusible element S1 is cleared after the device isagain tripped. Subsequently, the interrupting contacts 60 may be closedby reset assembly 17. The dual-solenoid 70′ may be energized for about100 milliseconds before it is damaged and burns out; thus, it is notdesigned to burn out during the interval that SCR Q1 is conductive(i.e., about 25 milliseconds).

Miswiring is also prevented on re-installation. Referring back to thewatchdog circuit 421, the charging path includes resistors R21, R27 anddiode D9 disposed between load hot and watchdog capacitor C12 coupled toload neutral. When the device is miswired, i.e., when the AC sourcevoltage is connected to the load terminals, the capacitor C12 is chargedup. As with an end of life condition, the voltage on C12 becomes greaterthan the breakover voltage of diac Q3. When the reset button 17 ismanually operated attempting to reset the device, the watchdog circuit421 will energize the dual-solenoid 70′ to thereby trip the circuitinterrupter 60. Each time reset is attempted; this process keepsrepeating itself, until device 10 is properly wired. When power isproperly applied to the line terminals and circuit interrupter 60 is inthe tripped state, capacitor C12 will not charge due to the circuitinterrupting contacts being open, and so device 10 can be reset.

Miswire protection on re-installation is afforded by coupling thewatch-dog capacitor C12 to the load side of circuit interrupter 60. Theother circuitry including the GFCI detector is coupled to the line sideof circuit interrupter 60. The two opto-isolators, (U2, U3) electricallyisolate these line side and load side circuits when circuit interrupter60 is in the tripped state. Summarizing, opto-isolator U2 couples adrive signal from the line side circuit to the load side circuit.Opto-isolator U3 couples a drive signal from the load side circuit backto the line side circuit.

In reference to the indicator circuit 418, once the device 10 trips, thecurrent from line hot 14-10 is diverted from the auxiliary switch 422and through LED D10, depicted as LED 17-2 in FIG. 15, such that LED D10is illuminated. If the auxiliary switch 422 is opened because SCR 410failed to turn ON during an auto-test or because of miswiring, theindicator driving circuit 416 will cause the indicator LED D10 to flash.Note that SCR 410 (Q1) is also coupled to the indicator driving circuit416. Specifically, when SCR 410 is turned ON as a result of theauto-test cycle, it is also configured to discharge capacitor C15 inaddition to the watchdog capacitor C12. If SCR 410 fails to turn ON forfour or five line cycles, the voltage on C15 becomes greater than thebreakover voltage of diac Q5 such that Q5 begins to conduct. When diacQ5 conducts, SCR Q6 is turned ON causing transistor Q7 to momentarilyturn ON. When Q7 is ON, current is diverted away from LED D10 and it isturned OFF. Q7 is only ON momentarily because diac Q5 will turn OFF whenthe voltage on capacitor C15 drops about seven (7) volts. Once diac Q5stops conducting, capacitor C15 will charge up again and the cycle willrepeat. Briefly, stated, the indicator LED D10 will provide a flashingred light indicating the device 10 has reached an end of life condition.The flashing light will continue until the consumer removes the device10 from the source of AC power.

Referring to FIG. 24, a schematic view of an arc fault circuitinterrupter in accordance with an embodiment of the present invention isdisclosed. The AFCI 90 may be implemented using any of the form factorsdescribed herein (i.e., FIG. 1, 3, 10, 11 or 21). The end of lifedetection feature and the miswire prevention features may be adapted toAFCI 90 (i.e. FIG. 22 or 23.) AFCI 90 protects an electrical circuit andincludes at least a neutral conductor 900 and a line conductor 901connected to a power source (not shown). A ground conductor (not shown)is optionally present. AFCI 90 detects electrical arcs occurring betweenline conductor 901 and ground, neutral conductor 900 and ground shouldthe power source be of reverse polarity, or line conductor 901 andneutral conductor 900.

A circuit interrupter 902 is disposed between the line conductor 901 andthe load 99. This embodiment incorporates a first stage arc sensor 920,shown as a current transformer, which is configured to respond to therate of change of neutral and/or hot conductor current with respect totime. Sensor 920 may be designed with a physically small core of a typeand number of secondary turns which gives optimum sensitivity duringarcing. Either a single conductor (hot line) or both conductors can passthru the sensor. The arc fault detector detects arcs that are either hotto ground or hot to neutral. The sensor 920 provides twodetector/amplifiers 921, 922 with sensor data. The detectors 921, 922may be implemented using any suitable device, such as an integratedcircuit used to detect ground faults (e.g., RV4141A). The detector 921is referred to as the di/dt stage, because it detects the change incurrent with respect to time. Detector 921 also has a high pass filtercapacitor 911 on its input side. The detector 922 is referred to as the60 Hz or “threshold” stage, and uses a low pass filter capacitor 912 ina feedback stage. The 60 Hz threshold detector 922 controls the level atwhich an arcing condition is to be detected, e.g., at a 75 Ampere orgreater load current.

The outputs of both stages are combined by a logic AND gate 913, andthis output is further combined by a second logic AND gate 914 with atimer output. Stated differently, the input current signal must exhibita rate of change that exceeds a predetermined rate, and a magnitude inexcess of a predetermined threshold, within the time frame selected bythe dimmer delay timer 952. If these conditions are met, a positivepulse is applied to the base of Q3 such that SCR 954 is turned ON. Thisenergizes the solenoid 960 to trip the circuit interrupter 902.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening.

The recitation of ranges of values herein are merely intended to serveas a shorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein.

All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. The use of any and all examples, or exemplary language (e.g.,“such as”) provided herein, is intended merely to better illuminateembodiments of the invention and does not impose a limitation on thescope of the invention unless otherwise claimed.

No language in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention. Itwill be apparent to those skilled in the art that various modificationsand variations can be made to the present invention without departingfrom the spirit and scope of the invention. There is no intention tolimit the invention to the specific form or forms disclosed, but on thecontrary, the intention is to cover all modifications, alternativeconstructions, and equivalents falling within the spirit and scope ofthe invention, as defined in the appended claims. Thus, it is intendedthat the present invention cover the modifications and variations ofthis invention provided they come within the scope of the appendedclaims and their equivalents.

What is claimed is:
 1. A protective device comprising: a plurality ofline terminals, a plurality of feed-through load terminals and a groundconnection element accessible via a back body; a cover assemblyincluding a plurality of receptacle openings, a reset button and a testbutton, the reset button and the test button being disposed along afirst diagonal and in opposite corners of a substantially square areadefined by the reset button and test button; at least one receptaclecontact structure including a portion extending across the firstdiagonal and at least one receptacle contact substantially aligned withone of the receptacle openings; an electromechanical apparatus disposedin the back body within a region substantially aligned with thesubstantially square area, the electromechanical apparatus including atoroidal sensor assembly coupled to an actuator coil arranged along acenter axis in substantial alignment with the first diagonal, the centeraxis forming an acute angle relative to a side wall of the back body,the actuator coil providing an actuation stimulus in response to adetected fault condition; and a circuit interrupter configured to renderthe plurality of line terminals, the plurality of feed-through loadterminals and the at least one receptacle contact structure electricallydiscontinuous in response to the actuation stimulus and electricallycontinuous in response to an actuation of the reset button.
 2. Thedevice of claim 1, wherein the cover assembly has a substantiallyrectangular shape.
 3. The device of claim 2, wherein the substantiallyrectangular shape includes a raised portion configured to accommodatethe substantially square area.
 4. The device of claim 1, wherein aseparator assembly is disposed between the cover assembly and the backbody, the separator assembly including a nonconductive cover portion anda nonconductive separator underbody.
 5. The device of claim 4, whereinthe separator assembly is disposed in its entirety inside a housingformed by the back body and cover assembly.
 6. The device of claim 4,wherein the at least one receptacle contact structure is substantiallydisposed between the nonconductive cover portion and the nonconductiveseparator underbody.
 7. The device of claim 6, wherein the at least onereceptacle contact structure includes a fixed contact accessible via anopening formed in the nonconductive separator underbody.
 8. The deviceof claim 4, further comprising at least one shutter assembly disposed inthe nonconductive cover portion between the at least one receptaclecontact and the receptacle opening aligned thereto.
 9. The device ofclaim 4, further comprising a ground strap connected to the groundconnection element, the ground strap being disposed in the nonconductivecover portion.
 10. The device of claim 9, wherein the nonconductivecover portion is configured to electrically isolate the ground strapfrom the at least one receptacle contact structure.
 11. The device ofclaim 9, wherein the ground strap does not include any external mountingelements configured to mount the device to a wall box.
 12. The device ofclaim 9, wherein the ground connection element is partially disposedwithin a wall portion of the back body.
 13. The device of claim 9,wherein the ground connection element includes a ground wire coupled tothe ground strap.
 14. An electrical wiring system including theprotective device of claim 1, comprising: a frame configured to bemounted to a device wall box, the frame including a first edge formedaround a peripheral portion of the frame, the first edge beingconfigured to abut a structural surface disposed around the device wallbox, the frame assembly further including a frame opening correspondingto at least one gang opening, the frame opening substantially defining asecond edge configured to extend inwardly toward the device wall boxinterior such that the frame opening provides sole access to the devicewall box interior; and the protective device of claim 1, the devicebeing configured to be coupled within the frame opening to complete thesystem enclosure such that the device wall box interior is substantiallyinaccessible.
 15. The system of claim 14, further comprising anaesthetic overlay configured to be removably coupled to the frameassembly, the aesthetic overlay including an overlay opening configuredto provide access to at least a portion of the cover assembly.
 16. Thedevice of claim 1, wherein the ground strap includes external mountingelements disposed at either end thereof, and wherein the groundconnection element includes a ground screw terminal disposed external tothe back body.
 17. The device of claim 1, wherein the plurality ofreceptacle openings includes a first set of receptacle openings and asecond set of receptacle openings, the first set of receptacle openingsand the second set of receptacle openings being disposed along a seconddiagonal and in opposite corners of the substantially square area, thefirst diagonal intersecting the second diagonal at approximately acentral portion of the substantially square area.
 18. The device ofclaim 17, wherein the at least one receptacle contact structure includesa hot receptacle contact structure and a neutral receptacle contactstructure.
 19. The device of claim 18, wherein the hot receptaclecontact structure is disposed substantially along a central longitudinalaxis and the neutral contact structure includes a neutral portionextending across the first diagonal.
 20. The device of claim 18, whereinthe neutral receptacle contact structure is disposed substantially alonga central longitudinal axis and the hot contact structure includes a hotportion extending across the first diagonal.
 21. The device of claim 1,wherein the circuit interrupter includes at least one movable linecontact structure having a movable line contact, at least one movableload contact structure having a movable load contact, and at least onefixed contact coupled to the at least one receptacle contact structure.22. The device of claim 21, wherein the at least one movable linecontact structure and the at least one movable load contact structureform an acute angle, the movable load contact, the movable line contactand the at least one fixed contact being vertically aligned at a vertexof the acute angle.
 23. The device of claim 21, wherein the at least onemovable line contact structure is substantially parallel to the firstdiagonal.
 24. The device of claim 21, wherein at least one moveable loadcontact structure is folded over to form a substantially u-shapedportion.
 25. The device of claim 21, wherein at least one moveable loadcontact structure includes either a dual contact or contact that isstaggered relative to a fixed contact.
 26. The device of claim 1,further comprising a latch block assembly configured to latch a pinportion of the reset button and lift either a movable line contactstructure or a movable load contact structure to effect reset, andunlatch the pin portion to effect tripping.
 27. The device of claim 26,wherein the latch block assembly includes an upper portion configured toapply a break force to a movable line contact structure or a movableload contact structure during a tripping action.
 28. The device of claim26, wherein the latch block assembly includes an upper portionconfigured to apply break force to a first end portion of the movableline contact structure therewithin, the movable line contact structurebeing fixed at a second end thereof within the toroidal sensor assembly.29. The device of claim 28, wherein the upper portion includes a firstbreaker arm configured to separate the movable line contact structurefrom a fixed receptacle contact during the tripping action, and a secondbreaker arm vertically and horizontally offset from the first breakerarm, the second breaker arm being configured to separate the movableload contact structure from the movable line contact structure duringthe tripping action.
 30. The device of claim 26, wherein the latch blockassembly includes a switch actuator coupled to an auxiliary switchconfigured to operate in tandem with the circuit interrupter, theauxiliary switch substantially decoupling a portion of theelectro-mechanical apparatus from the plurality of line terminals afterthe circuit interrupter has rendered the plurality of line terminals,the plurality of feed-through load terminals and the at least onereceptacle contact structure electrically discontinuous.
 31. The deviceof claim 1, wherein the electro-mechanical apparatus includes at leastone detection circuit configured to detect the fault condition, thefault condition being selected from a group of fault conditionsincluding an arc fault, a ground fault, a grounded neutral fault, amiswire fault, or a failed component fault.
 32. The device of claim 31,wherein the at least one detection circuit includes a circuit segmentcoupled between the line terminals and configured to conduct apredetermined signal in response to detecting a proper wiring condition,the predetermined signal not simulating a fault condition, the properwiring condition being effected when the line terminals are connected toa source of AC power, the circuit interrupter being substantiallyprevented from effecting a reset state absent the predetermined signalbeing conducted by the at least one detection circuit.
 33. The device ofclaim 31, wherein the at least one detection circuit includes a wiringstate detection circuit coupled across the plurality of line terminals,the plurality of feed-through load terminals or a plurality ofreceptacle contact structures.
 34. The device of claim 31, wherein theat least one detection circuit includes: a test circuit configured toautomatically provide the toroidal sensor assembly with a test signal; afault detection circuit configured to generate a test detection signalin response to detecting the test signal, the actuator coil notproviding an actuation stimulus in response to the test detectionsignal; a counting circuit coupled between the plurality of feed-throughload terminals or a plurality of receptacle contacts and the faultdetection circuit, the counting circuit including a timer circuit, thecounting circuit being configured to reset the timer circuit in responseto detecting a first optical signal corresponding to the test detectionsignal, the timer circuit providing an elapsed time signal in theabsence of a timely test detection signal; and a test response circuitcoupled to the counting circuit, the test response circuit providing asecond optical signal in response to the elapsed time signal, the faultdetection circuit converting the second optical signal into a faultdetection signal, the actuator coil providing an actuation stimulus inresponse to the fault detection signal.
 35. The device of claim 34,wherein the fault detection signal corresponds to either a miswire faultcondition or a failed component fault condition.
 36. The device of claim1, further comprising a bidirectional optical interface configured tocommunicate test data between portions of a test apparatus.
 37. Thedevice of claim 36, wherein the bidirectional optical interface includesa first opto-coupler device configured to provide a test fault detectionsignal from a fault detection circuit disposed within theelectromechanical apparatus, and a second opto-coupler device configuredto transmit a test failure detection signal to an alarm processingcircuit disposed within the electromechanical apparatus.
 38. The deviceof claim 37, further comprising a timing device configured to providethe test failure detection signal to the second opto-coupler device inthe event that the test fault detection signal fails to reset the timingdevice within a predetermined period of time, the test failure detectionsignal being configured to trip the circuit interrupter.
 39. The deviceof claim 1, further comprising an indicator circuit coupled to theelectro-mechanical apparatus.
 40. The device of claim 39, wherein theindicator circuit provides a fault indication selected from a group offault indications including a proper wiring state indication, amiswiring state indication, a failed component indication, a tripindication, or a reset indication.
 41. The device of claim 40, whereinthe indicator circuit includes a visual indicator that blinks inresponse to the failed component.
 42. The device of claim 1, wherein thereset button has a user accessible surface in which an LED tripindicator is disposed.
 43. An electrical wiring system comprising: aframe assembly configured to be mounted to a device wall box installedin a structure, the frame including a first edge formed around aperipheral portion of the frame, the first edge being configured to abuta structural surface disposed around the device wall box, the frameassembly including a ground portion configured to provide a ground pathfrom the frame assembly to ground, the frame assembly further includinga frame opening corresponding to at least one gang opening, the frameopening substantially defining a second edge configured to extendinwardly toward the device wall box interior such that the frame openingprovides sole access to the device wall box interior; a protectivedevice configured to snap-mount within the frame opening, the protectivedevice comprising, a plurality of line terminals, a plurality offeed-through load terminals and a ground connection element configuredto contact the frame such that the ground connection and the ground pathare electrically continuous, a cover assembly including a plurality ofreceptacle openings, a reset button and a test button, the reset buttonand the test button being disposed along a first diagonal and inopposite corners of a substantially square area defined by the resetbutton and test button, an electromechanical apparatus disposed in theback body portion within a region substantially aligned with thesubstantially square area, the electromechanical apparatus including atoroidal sensor assembly coupled to an actuator coil arranged along acenter axis in substantial alignment with the first diagonal, the centeraxis forming an acute angle relative to a side wall of the back body,the actuator coil providing an actuation stimulus in response to adetected fault condition, and a circuit interrupter configured to renderthe plurality of line terminals, the plurality of feed-through loadterminals and the at least one receptacle contact structure electricallydiscontinuous in response to the actuation stimulus and electricallycontinuous in response to an actuation of the reset button; and anaesthetic overlay configured to be removably coupled to the frameassembly, the aesthetic overlay including an overlay opening configuredto provide access to at least a portion of the cover assembly.
 44. Thesystem of claim 43, wherein the protective device is configured tooccupy the space of a one gang opening.
 45. The device of claim 43,wherein the cover assembly has a substantially rectangular shape. 46.The device of claim 43, wherein the substantially rectangular shapeincludes a raised portion configured to accommodate the substantiallysquare area.